Development and application of multi-axis hybrid simulation for seismic stability of steel braced frames

This paper presents the development and application of multi-axis pseudo-dynamic hybrid simulation for eval-uating the seismic stability of steel braced frame structures. The advanced hybrid testing system used to perform hybrid simulation is first described, followed by the development of hybrid simulation and main challenges, namely the friction forces generated in the testing system and high-frequency noise in force feedback signals. The strategies proposed to overcome these challenges are then described. Two pseudo-dynamic hybrid simulations consisting of a two-tiered concentrically braced frame where a full-scale wide-flange column part of the frame is physically tested while the rest of the frame is numerically analysed are finally presented. The test results serve to verify the hybrid simulation technique, evaluate experimentally the seismic stability response of columns of steel multi-tiered concentrically braced frames and validate the findings of past fibre-based numerical models used to assess the seismic response of multi-tiered braced frames.